1. Technical Field
The invention relates to kitchen appliances generally and, in particular to an apparatus for brewing coffee.
2. Related Art
Coffee drinkers are often a picky lot. It is difficult to speak in terms of likes and dislikes for the coffee consuming public. People in the coffee industry often look at the extraction rate for a particular combination of coffee variables (including blend, grind, moisture and roast color). “Extraction rate” is the amount of soluble solids that pass from coffee beans to brewed coffee and give it body and flavor. Coffee may be thin or “underextracted,” meaning that not enough soluble solids came out. Harshly potent coffee is referred to as “overextracted,” meaning that too many soluble solids came out.
The extraction rate also depends on the type of coffee maker used. Among other variables, the water temperature (the ideal water temperature is about 195 to 205 degrees F.—not a rolling boil, otherwise bitter substances will be extracted), water pressure, blend, the grind type, the filter type and the contact time between water and ground all figure into the extraction rate. This may explain why there are so many different types of coffee makers, such as electric drip, moka, Napoletana, percolators, expresso and French presses.
Drip coffee is the most common home-brewing method in which hot water drips through ground coffee at the force of gravity. Electric drip is the most common form of coffee maker. “Mokas” use steam pressure (about 3.5 bars) from boiling water in a closed chamber to force the hot water to escape from the chamber and pass through ground coffee to produce coffee. Because of the steam temperatures, mokas tend to make bitter coffee. They also tend to require the brewing of multiple cups of coffee rather than a single cup. A “napoletana” has an lower chamber for boiling water and an upper chamber with a spout and in between a ground coffee compartment. After water boils in the lower chamber, the pot is flipped over and the water drips through the ground coffee into the part with a spout. Napoletanas are messy and result in a strong cup of coffee. “Percolators” recycle boiling water through ground coffee filtered through a perforated metal or even a ceramic screen, producing a bitter, sour brew. “French presses” steep the coffee grounds in water, like tea leaves, then a finely perforated metal screen is pressed down through the liquid to separate the grounds from the brewed coffee. This results in strong often bitter coffee taste profile.
Espresso is a popular type of coffee. “Espresso” is a method of brewing coffee by forcing hot water at very high pressure (approximately 9 bars) through finely ground coffee, producing a syrupy texture and a powerful, sweet taste. Generally only a “pump machine” produces true espresso at home. Pump machines have a small electric pump produce high pressure to force hot water through finely ground coffee. “Steam machine” which rely on pressure from built up steam in the fluid path—are also generally billed as espresso makers but may not produce sufficient pressure (9 bars) for true espresso. These very high pressure requirement make manufacturing espresso machines expensive. Larger pumps and reenforced fluid paths, boilers, etc. are required to ensure safety and reliability. However, espresso machines frequently allow users to make one or two small cups of espresso quickly with a pleasing strong taste and crema. “Crema” is the a golden foam made up of oil and colloids that floats atop the surface of a perfectly brewed cup of espresso. Achieving crema depends on a number of factors, but most importantly the degree of pressure used in brewing. Some machines achieve sufficient pressure by mixing the coffee liquid with air after brewing by forcing it through a tiny opening.
The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. In the figures, like reference numerals designate corresponding parts throughout the different views.
The apparatus preferrably has a base 115 that may support up to two coffee cups 117. As would be readily understood, apparatus 100 may be used with vessels other than coffee cups. The base may also include a drain cover and overflow reservoir to catch fluid not caught by coffee cup 117. A power switch 120 selectively connects the apparatus 100 to an electrical power supply, such as main power. As would be known to those skilled in the art, apparatus 100 will include one or more voltage regulator/transformers as needed to supply the appropriate power to the various electrical components of the apparatus. As shown in
As also shown in
Water reservoir 102 is in fluid communication with flow meter 200. Preferrably, the water reservoir is constructed to contain approximately 28 ounces of water (essentially enough for 3, 8 oz cups or 5, 5 oz cups of brewed liquid). An optional valve 103 may be disposed on the water reservoir 102 such that water will not flow from the reservoir unless it is properly connected to the fluid path. This allows removal of the water reservoir 102 for refilling in a sink. Optional valve 103 is preferrably a mechanical valve that is biased closed upon removal from the fluid path and remains open during fluid communication between the water reservoir 102 and the fluid path. Water reservoir 102 may additionally or alternatively have an open mouth to allow water to be poured into the reservoir without removing it from the rest of apparatus 100.
Flow meter 200 is essentially a switch that controls the volume of water that is fed through the fluid path. In the preferred embodiment, flow meter 200 has a housing that encloses a turbine with a magnet embedded therein. As water flows through the flow meter, the turbine rotates the magnet, which rotation is sensed by a hall effect sensor mounted in association with the flow meter housing. In this manner, a controller (not shown) can count the number of turns of the turbine. The number of turns corresponds to a volume of water flowed. Thus, once the turbine rotates a desired number of times, the desired volume of water has been flowed into the fluid path. As discussed above, the controller may store more than one preset volume of water such that the end user can select the amount of brewed fluid produced by apparatus 100.
Pump 202 is in fluid communication with both flow meter 200 and boiler 204. In one embodiment, pump 202 is an electric pump generating approximately 1.5 bars of pressure. In another embodiment, pump 202 generates approximately 3.5 bars of pressure. With 3.5 bars of pressure, it has been determined that apparatus 100 can produce acceptable crema from coffee pod 1100 (discussed below). It is contemplated that the fluid path, boiler, by-pass valve and flow meter of apparatus 100 can simply be built to accommodate this higher pressure allowing the apparatus to use a pump having either pressure. Moreover because this higher pressure is much lower than the pressure required to produce espresso (generally thought to be approximately 9 bars), this 3.5 bar pressure requirement does not significantly raise the cost of the fluid path above that required to safely support 1.5 bars of pressure. This makes dual pressure this construction practical. It is contemplated that apparatus 100 could use a pump that can produce both 1.5 and 3.5 bars of pressure. In such a case, a switch would be provided to select between these pressures. This switch could be made available only to the manufacturer or provided to the end user so as to allow selection of either pressure to achieve different taste profiles.
Boiler 204 is in fluid communication with the pump 202 and by-pass valve 206. Boiler 204 preferrably has a volume of approximately 340 c.c. (or 12 ounces). Boiler 204 is electric and preferrably quickly heats the water to a desired preset temperature. While it is possible that boiler 204 could be a steam boiler, the use of steam would increase the water requirements of apparatus 100 along with its safety requirements (to protect against the steam pressures generated in such boilers) and, thus is considered to be generally undesirable.
By-pass valve 206 ensures that the pressure in the fluid path does not exceed the nominal pressure selected for apparatus 100. So, in an embodiment allowing for two pressures (e.g. approximately 1.5 and 3.5 bars), the by-pass valve would be selected to vent any pressure in the fluid path sufficiently in excess of 3.5 bars to cause safety and/or structural concerns.
Hot water from the fluid path flows out through a shower 300 in brewhead 104. As shown in
Latch 106 mechanically grabs a slot on the upper surface 304 of housing 112 to maintain closure. Gasket 306 encircles the circumference of the shower 300 and the top of pod holder assembly 110 to substantially preclude hot fluid from spreading out across upper surface 304 and possibly down the sides of housing 112 potentially producing an undesirable mess during operation.
Pod cup 401 receives and supports a pod 1100 (see
By selecting the diameter of pod cup 401, number of holes in the sieved bottom of pod cup 401 and the diameter of each hole in the sieve, the range of time that the hot water remains in contact with the brewable solids can be substantially controlled. The preferred embodiment of pod cup 401 is shown in
In the preferred embodiment, fluid cup 403 and fluid nozzle 404 together form a fluid conduit positioned to receive all of the fluid passing through the plurality of apertures in the sieved bottom of pod cup 401. This fluid conduit further conveys the received fluid into one or more coffee cups 117 (see
As previously explained, in a preferred embodiment, the pod holder assembly 110 may be removed or replaced. In an embodiment where replacement is possible, a user may select different pod holder assemblies 110 for different purposes. For example, for coffee, it is common for a user to have a shorter cup 117 such as a coffee mug. In this case, the coffee may splash out if the fluid nozzle 404 is too far away from the cup 117. Thus, it is preferable to have a pod holder assembly 110 with a longer fluid nozzle 404 so as to bring the coffee closer to the cup as the fluid leaves the nozzle 404. On the other hand, for drinking iced tea, it is more common to use a taller glass. In such a case, a long fluid nozzle 404 may be too long to allow the glass to fit under the pod holder assembly 110 to catch the brewed fluid. Thus, a pod holder assembly 110 having a shorter fluid nozzle 404 to accommodate a tall glass 117 may be used.
Additionally, it may also be desirable to simply have two or more interchangeable fluid nozzles 404a and 404b of the same (or differing) length, with associated fluid cups 403a and 403b, pod cup handles 402a and 402b and pod cups 401a and 401b. For instance, one nozzle could be used for coffee beverages and another for tea beverages. In this way, the undesirable introduction of a “coffee taste” into the brewed tea beverages may be avoided. In one embodiment, the different interchangeable fluid nozzles 404a and 404b may be differentiated by some indicia of distinction, for example a descriptive label or color.
With this embodiment illustrated in
In the preferred embodiment, the pod has the dimensions shown in
Grind type is determined by using an Alpine Analysis with 20 inches of vacuum. Type A has 0% at #16 Screen; 1% at #20 Screen; 6% at #30 Screen; 45% at #40 Screen; 70% at #50 Screen; 0% at #100 Screen and 0% at the pan. Type B has 0% at #16 Screen; 1% at #20 Screen; 13% at #30 Screen; 54% at #40 Screen; 76% at #50 Screen; 0% at #100 Screen and 0% at the pan.
Coffee flavoring is achieved by spraying the coffee with oils and extracts, or dusted with powders. 3.0% equates to 3.0 ounces of flavoring for every 1 lb. of roasted coffee.
Apparatus 100 achieves a method of brewing foodstuffs. The end user places pod 1100 containing ground, brewable foodstuffs 1200 into pod holder 402. The measured volume water is heated by a boiler. The apparatus pumps a metered volume of water at a selected fluid pressure. In one method, the apparatus first pumps a small amount of water to pre-infuse the pod. This pre-infusion involves pre-wetting the pod 1100 with water to assist in brewing, which preferrably occurs for 5 seconds. Eventually, the heated metered volume of water at the selected fluid pressure is fed to the pod located in the pod holder resulting in a fluid having a desired amount of soluble solids. That brew fluid is passed into a coffee cup.
While various embodiments of the application have been described, it will be apparent to those of ordinary skill in the art that many more embodiments and implementations are possible that are within the scope of this invention. Accordingly, the invention is not to be restricted except in light of the attached claims and their equivalent.
The present application is a continuation-in-part of PCT application No. PCT/US04/13725 filed May 3, 2004 and claims priority to U.S. Ser. No. 60/468,115 filed May 2, 2003, which applications are incorporated herein by reference to the extent permitted by law.
Number | Date | Country | |
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60468115 | May 2003 | US |
Number | Date | Country | |
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Parent | PCT/US04/13725 | May 2004 | US |
Child | 10985422 | Nov 2004 | US |